Nice: French President Francois Hollande said on Friday that "many foreigners and young children" were among those killed or injured after the truck attack on a crowd celebrating Bastille Day in Nice, with around 50 fighting for their lives.

French President Francois Hollande. Reuters

"There are French among the victims and also many foreigners from every continent and many children, young children," said a clearly moved Hollande in a speech from a hospital in the French Riviera city.

"As I speak 84 people are dead, and around 50 are in a critical condition between life and death," he added.

Witnesses said a truck drove at speed into a crowd for two kilometres (1.3 miles) after around 30,000 people had been watching a fireworks display on France's national day.

Hollande previously described the attack on the palm-lined Promenade des Anglais as being of an "undeniable terrorist nature".